Which sequence correctly describes the Congo red staining procedure?

Study for the CAMLPR Histology Practice Test. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

Understanding the sequence used for Congo red staining in amyloid detection helps you see why this order gives you crisp contrast and specific labeling. Start with Harris hematoxylin because it provides a stable nuclear counterstain, giving clear blue nuclei that will remain visible through subsequent steps. Next, apply the alkaline salt differentiator to remove non-specific or weakly bound dye and to prepare the tissue so that the Congo red binds primarily to amyloid rather than to other components. Finally, treat with Congo red solution; Congo red binds to amyloid deposits, producing red staining that stands out against the hematoxylin background. Under polarized light, these amyloid deposits will show apple-green birefringence, confirming their presence. Other sequences can obscure nuclear detail or reduce the specificity of Congo red binding, making this order the best choice for clear, interpretable results.